The aspirational claims and investment losses in the CIGS photovoltaic materials system have kept Greentech Media busy over the last few years. From Solyndra to MiaSolé to Nanosolar to AQT to SoloPower, the siren song of silicon efficiency at thin film costs had long kept the CIGS hype — and funding — flowing freely.
Now, the funding has stopped. As has the hype.
But the efficiency numbers continue to tantalize.
Despite the lack of volume commercial sales (with the exception of Solar Frontier), the efficiency side of CIGS continues to improve. This week, we had two champion module reports in CIGS:
- Taiwan’s semiconductor foundry giant TSMC posted a champion module efficiency of 15.7 percent with its Stion-licensed technology. Actual shipment volume from TSMC remains small and unreported. TSMC also notes that it has made gains in the module’s temperature coefficient, improving performance in hot environments.
- Japan’s Solar Frontier claims a 14.6-percent-efficient CIS PV champion module on its factory production line. Solar Frontier does not disclose its costs, but a contact close to the firm indicates that the current module design is “cost-rich.”
Solexant CEO Brad Mattson has suggested that a preoccupation with efficiency records is the wrong mindset and is more an indication of an uncontrolled manufacturing process. Mattson believes that the best process for manufacturing is co-evaporated CIGS in a roll-to-roll process because it’s “higher efficiency than anything else.” Solexant’s hire of Markus Beck might have had an influence on that process choice. Mattson sees Solexant as combining the highest efficiency science with the highest tool capability. It has to be “repeatable and fast.” Mattson also predicts that the thin film industry will be populated by five players within a few years, none of which will be Solar Frontier.
“The challenge isn’t the science. It’s an equipment challenge. It’s engineering. And it can be done,” Mattson told GTM in an earlier interview.
Mattson realizes the challenge in CIGS, saying, “CdTe wants to go together well. CIGS is the opposite — the materials want to do many things. It’s difficult but allows for concentration gradients. You can dope CIGS, but it is more of a challenge to control.” Solexant has also studied the tradeoffs between singulating cells and monolithic deposition.
Mattson looks to “apply semiconductor process control” and “focus on speed,” with a minimum line size of 250 megawatts and one that is as fully automated as possible.
Here’s a partial list of CIGS solar players, past and present:
- Solar Frontier, 577 megawatts shipped in 2011
- Solibro, 95 megawatts shipped in 2011 (sold to Hanergy)
- MiaSolé, 60 megawatts shipped in 2011 (sold to Hanergy)
- Solyndra (bankrupt)
- Global Solar (now selling only consumer solar products)
- Soltecture (bankrupt)
- Nanosolar (recent RIF, company for sale, reports have Hanergy hiring a number of ex-Nanosolar employees)
- AQT (bankrupt)
- HelioVolt (no commercial production, majority owner is SK Innovations)
- Ascent Solar (majority owner is TFG Radiant)
- ISET (limited commercial production, company is transitioning to “micro-solar components”)
- Stion (limited commercial production, allied with TSMC)
- SoloPower, limited commercial production
- Solexant (Solexant acquired the remains of Wakonda)
- TSMC (technology licensed from Stion)
- NuvoSun (acquired by Dow)
While we’re discussing efficiency records, First Solar (FSLR), the thin-film solar leader, holds the cadmium telluride solar module efficiency record with an NREL-confirmed efficiency of 16.1 percent. First Solar also set a high mark for CdTe open-circuit voltage, an indicator of PV panel performance, hitting 903.2 millivolts. First Solar set a new world record for CdTe solar cell efficiency of 18.7 percent as well. However, setting records is one thing, translating that to commercial shipments is another — and it’s something First Solar has done well over the years.
First Solar’s average production module efficiency was 12.9 percent in the fourth quarter of 2012, while its “lead line” was producing modules with 13.1 percent efficiency during the fourth quarter.